This invention relates to a hose for use in cleaners of the power nozzle type, and more particularly to improvements in a cleaner hose which is electrically conductive and which has embedded therein helical conductors for electrically connecting a switch for a drive device on the forward end of the hose to a main switch mounted on a hose gripping portion and positioned closer to the main body of a cleaner.
Conductive cleaner hoses of this type heretofore known include those in which copper wires helically wound on and attached to the inner surface of a bellows-shaped hose wall for reinforcing the hose serve also as conductors. With such hoses, reinforcing copper wire conductors of large diameter having a sufficient load capacity to pass great current, if used, will seriously impair properties such as stretchability and flexibility which are essentially required of the hoses. Conversely, the use of copper wires of small diameter as conductors and reinforcing elements so as to ensure improved stretchability and higher flexibility entails a voltage drop, rendering the copper wires unable to pass great current, and further involves the drawback that the copper wires fail to give sufficient strength for the hose to retain its shape. Consequently, when the hose is repeatedly subjected to external forces as by being trampled, stretched or bent during use, the copper wires soon will break and become unable to provide reinforcement for the hose and to serve as a conductor.
Another cleaner hose is known which comprises a bellows-shaped hose main body and two reinforcing elements of thermoplastic elastic material arranged side by side and helically wound around and attached to the outer surface of the hose main body, each of the reinforcing helical elements having embedded therein a conductor composed of a hard steel wire and twisted copper wires wound around the hard steel wire. The conductor embedded in the helical element has a relatively large diameter and therefore has the advantage of being capable of passing greater current than those of the conventional hoses described. However, the conductor-incorporating reinforcing helical elements which are arranged on the outer surface of the hose are liable to wear away early from outside to expose the conductors since the hose is invariably dragged during the use of the cleaner. As a result, troubles such as a short circuit or electric shock are very likely to develop. Moreover, the reinforcing elements of increased cross sectional area required have the drawback of rendering the hose less stretchable and flexible.